Skimmer pools are the most popular type. Although not the most expensive solution, proper design and construction can lead to outstanding results.
Skimmer pools have rectangular openings on the sides of the pool that draw water from the surface, where most contaminants (like debris, insects, hair, body oils etc) are.
Skimmers are designed to pull those contaminants into the basket strainer and a swinging door located inside the opening ensures they cannot get back into the pool.
In order to clean and maintain skimmers there is an access hatch above the strainer basket that allows to empty and clean the baskets regularly, to ensure optimal flow.